Use of endosseous dental implants for the foundation for various dental restorations, like bridges, crowns, dentures and the like is well known in the art. Positioning of the dental implant is absolutely critical. For many well known reasons, long term success of the implant, and ultimately of the restoration, hinges on drilling a correct placement, diameter, depth and alignment of a socket or the like for receiving the implant. It will be appreciated that this necessitates careful planning as well as careful formation of the socket.
A conventional and well known method of implanting solid screw implants will be briefly reviewed to provide some background regarding the need for and process of careful preparation of the implant bed. A first step of the procedure involves exposing the bone ridge and preparation of the implant bed for receiving the implant or implants. The ridge is flattened as necessary with a relatively large bur, e.g. a Ø3.1 mm (3.1 mm diameter) round bur at a maximum of 800 R.P.M. (revolutions per minute). The flattened site may be marked with a small round bur (Ø1.4 mm) at the center of the intended bore for the hole or socket in which the implant is to be positioned.
After preparation of the site, a pilot hole is formed at the implant site with a pilot drill bit (Ø2.2 mm) is inserted to a depth equal to or slightly deeper than the insertion depth of the implant, for example approximately 6.0 mm for a 6 mm implant. Slight pressure should be used during drilling with sufficient cooling throughout the entire sequence.
The depth and alignment of the resulting pilot hole is checked with a Ø2.2 mm alignment pin. Both angle and depth of the pilot hole must be precise and since the operation is taking part in the patient mouth, it can be seen that there is an inherent difficulty with this technique, namely, both alignment and depth cannot be accurately gauged at the same time. Fortunately, an unsatisfactory implant axis can still be corrected at this step in the procedure. After the alignment of the pilot hole is checked and, if necessary, corrected, drilling continues with the Ø2.2 mm drill bit to the depth of the implant selected or slightly deeper and the depth is again checked with the Ø2.2 mm alignment pin. A Ø2.8 mm drill bit, also known in the industry as a pilot bit, may be used to widen the pilot hole to the appropriate depth. The depth is again checked with a Ø2.2/2.8 mm depth gauge.
If an Ø3.0 mm reduced diameter or narrow neck implant is being placed, the next step would be to tap the site and insert the implant. If not, a Ø3.5 mm twist drill bit is used to widen the initial hole to the appropriate depth. The depth is measured with a Ø3.5 mm depth gauge. If an Ø4.1 mm standard diameter implant is being placed, the next step would be to tap the site and insert the implant. If not, a Ø4.2 mm twist drill bit is used and the depth is checked with a Ø4.2 mm depth gauge. The site can then be tapped and an Ø4.8 mm wide diameter or wide neck implant may be inserted. It will be understood that the example given herein is illustrative and not limiting in nature. In general, to summarize, the preparation process includes drilling a pilot hole at the implant site at the correct position and angle and then widening the hole with at least a second sized drill to the correct width and depth to receive the implant. The second drill may also be a counterbore type drill in some instances. Further widening of the hole or socket is performed to accommodate a predetermined width and length of implant.
Each implant or post must form a solid, enduring base with sufficient stability to withstand the tremendous mechanical pressure involved in normal chewing, so typically three to six months are allowed for the implant to incorporate into or bond to the bone. During the wait, a temporary bridge or denture is provided to the patient to facilitate eating and to maintain facial muscle support; meanwhile, a lab custom designs and manufactures the restoration to be placed over the implant top(s).
Once the implant post has bonded with the jawbone, and the artificial teeth are ready, the final step of the implant placement process involves placing the prepared restoration(s) over the protruding implant post(s). This results in a secure, attractive, replacement tooth or set of teeth, designed to function as effectively as one's natural teeth. Depending on the number of teeth involved, this final part of the implant process requires only a short time to complete.
Since it is critical to accurately position and angle the socket and since it is critical to prepare the depth of the socket accurately, it can be seen that gauging the angle and depth by eye during drilling can be difficult indeed. Thus, there is a demand for a method and device to accurately prepare a socket for receiving a dental implant. The present invention satisfies the demand.